Montserrat Jiménez-Sánchez

Spatial distribution of paleoclimatic proxies in stalagmite slabs using laser-induced breakdown spectroscopy

The spatial distribution of paleoclimatic proxies in stalagmite slabs using laser-induced breakdown spectroscopy (LIBS) has been performed in this study. Stalagmites from different locations in the north of Spain were cut and analyzed along the main growth axis by LIBS. For comparative purposes, powders drilled from along the growth axis were also analyzed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Advantages of LIBS include fast analysis of long stalagmite sections at atmospheric pressure, lateral resolution in the μm range and no sample preparation beyond having optical access to the stalagmite section to be inspected. Mg/Ca and Sr/Ca intensity ratios are of major interest for paleoclimate applications. An excellent agreement between the Mg/Ca intensity ratios measured in LIBS and in ICP-AES was observed. Sr/Ca trends were well matched only in high Sr stalagmites. Also, this work reports the employment of detrital layers as paleoclimatic proxies in speleothems by LIBS. Large concentrations of Si and Al are indicative of flood events inside the cave.

The Picos de Europa National and Regional Parks

The E–W trending Cantabrian Mountains, with peaks more than 2,600 m a.s.l., are located along the northern coast of the Iberian Peninsula. After the development of south-verging structures during the Alpine Orogeny, the Cantabrian Mountains were arranged as an asymmetrical relief deeply dissected by the fluvial network, with steep rivers flowing into the Cantabrian Sea in the north and less steep rivers draining towards the Duero Tertiary Basin to the south. The area shows a high geomorphic diversity, including relict Quaternary glacial and periglacial landforms, as well as features related to slope instability, fluvial and karstic processes. This work summarizes the geomorphological features of two different protected areas of the Cantabrian Mountains designated as Picos de Europa: the Picos de Europa National Park and the Picos de Europa Regional Park. Both are representative areas of the high-mountain landscapes of the northern and southern sectors of the Cantabrian Mountains. Moreover, the former hosts good examples of underground alpine karst.

New evidence of sea-level lowstands and paleoenvironment during MIS 6 and 4 in the Cantabrian coastal karst: The Cobiheru cave (North Iberia)

The geomorphological evolution of the Cobiheru Cave shows the influence of the non-carbonate coastal mountain ranges on coastal karst evolution, as well as the temporal distribution of the cold-adapted fauna sites in the Cantabrian Coast. Geomorphological observation and U/Th dating lead to the construction of an evolution model. The model comprises two episodes of cave deposition occurred at ca. 60–70 and 130–150 ka, linked to cold climate conditions, global sea-level lowstands and the erosion of alluvial fans that covered the karst. Moreover, the comparison between the Cobiheru record and some raised beaches identified in previous studies sets the beginning of the sea-level lowering in the Cantabrian Sea during the MIS 5-4 transition. Two palaeoenvironments are inferred based on finding Equus ferus and Elona quimperiana. A wet deciduous forest would have been developed on the emerged marine terrace of the Cobiheru Cave since at least the Middle Pleistocene, and an open landscape with scarce vegetation would have been present at ca. 65 ka. The erosional event identified in the Cobiheru Cave helps to understand the temporal distribution of cold-adapted mammals located in the Asturias region. The probable sites of cold-adapted fauna developed in caves and alluvial fans would have disappeared after 65 ka. Therefore, palaeontological and palaeoclimate research based on cold-adapted mammals suggests the occurrence of an hiatus in the palaeontological record prior to 50 ka. This article is protected by copyright. All rights reserved.

Favorability functions based on kernel density estimation for logistic models: A case study

Susceptibility or hazard models are often established by means of logistic regression techniques in order to describe the effect of a group of explanatory variables on the probability of a dichotomous or binary response. Since the available variables do not always meet the assumptions of logit-linearity of the logistic regression, a modified approach is proposed. Firstly a favorability function associated with each explanatory variable based on the conditional probability measures is introduced. Next, a simple transformation based on the empirical probability function for non-continuous variables is suggested, while nonparametric kernel estimation is considered for continuous ones. The favorability-based transformations lead to new explanatory variables for the logistic regression model. The performance of the method is evaluated using simulated data. In addition, a real case-study is presented, in which a GIS-based landslides susceptibility model is carried out.

Cliff Coast of Asturias

The Principality of Asturias (or simply Asturias) is a region located in the North of Spain (SW of Europe) limited by the Cantabrian Sea in the North and the Castilla y Leon, Cantabria and Galicia regions in the South, East and West respectively. The Asturias Coast represents around 30% of the Cantabrian Coast, the northern limit of the Iberian Peninsula, and is surrounded by the Cantabrian Sea. This sea represents the transition of the Atlantic Ocean to the Biscay Gulf, between Spain and France. Towards the South, the Cantabrian Coast is limited by the Cantabrian Mountains, up to 2,648 m altitude, which axis is located only at 20–50 km from the sea.

Environmental Study of Cave Waters: A Case Study in Las Herrerías Cave (Llanes, Spain)

Las Herrerias Cave (Llanes, North Spain) is a relevant cave due to its cave palaeolithic paintings. It was declared of Good Object of Cultural Interest by the Asturias Regional Government. It is located in a karst Carboniferous aquifer which surface involves farming, livestock and tourist use, as well as a discrete mining activity and an old quarry converted into a waste area above the karst massif. A hydrogeological research was carried out from 2007 to 2010 focusing on the impact of land use on the cave. The aim of this work is to highlight the importance of using hydrochemistry monitoring to determinate the impact of the land use on cave waters. Several sampling campaigns of rainfall, the waters inside and outside the cave and El Bolau spring were carried out. A sampling device was installed inside the cave to collect discrete samples of dripwater each 48 h in 1.5 l bottles. The array contains 24 bottles and was deployed for 48 days intervals. Results evidence that calcium bicarbonate is the dominant chemical component in all the sampled water. Some of them, collected under the waste area, show high values in NO3 −, Ba2+, TOC, K+, SO4 2−, Silicium, Fe, Si, PO4 3−and Sr2+, being indicative of an adverse effect on the quality of drip water.